> Jetbrains IDEA was updating very slowly and when I wanted to pin a version of it simply overriding version variable in the overlay was not enough - there were

> Jetbrains IDEA was updating very slowly and when I wanted to pin a version of it simply overriding version variable in the overlay was not enough - there were also some other linked variables. Emacs package from custom overlay constantly tried to compile itself, requiring me to check build status on hydra build system. The way I solve this is to import multiple versions of Nixpkgs, since they're all self-contained. For example, if I'm upgrading from Nixpkgs/NixOS 21.05 to 21.11, and I find that package 'foo' has broken, or been removed, I'll do this in an overlay: self: super: { foo = self.nixpkgs2105.foo; } Where nixpkgs2105 is a pinned revision of the Nixpkgs repo, defined in another overlay. My current Nix config has pinned Nixpkgs versions going back to 2016. For example, here's a bunch of such overrides: https://github.com/Warbo/nix-config/blob/master/overrides/fixes.nix https://github.com/Warbo/nix-config/blob/master/overrides/fi... At the moment I'm using niv to manage the pinned Nixpkgs versions (the 'repoXXXX' entries): https://github.com/Warbo/nix-helpers/blob/master/nix/sources.json https://github.com/Warbo/nix-helpers/blob/master/nix/sources...